September 9337 – Constantine II, Constantius II, and Constans succeed their father Constantine I as co-emperors. The Roman Empire is divided between the three Augusti. 1000 – Battle of Svolder, Viking Age. 1141 – Yelü Dashi, the Liao dynasty general who founded the Qara Khitai, defeats the Seljuq and Kara-Khanid forces at the Battle of Qatwan. 1320 – In the Battle of Saint George, the Byzantines under Andronikos Asen ambush and defeat the forces of the Principality of Achaea, securing possession of Arcadia.
December 131294 – Saint Celestine V resigns the papacy after only five months to return to his previous life as an ascetic hermit. 1545 – The Council of Trent begins as the embodiment of the Counter-Reformation. 1577 – Sir Francis Drake sets sail from Plymouth, England, on his round-the-world voyage. 1623 – The Plymouth Colony establishes the system of trial by 12-men jury in the American colonies. 1636 – The Massachusetts Bay Colony organizes three militia regiments to defend the colony against the Pequot Indians, a date now considered the founding of the National Guard of the United States.
August 24367 – Gratian, son of Roman Emperor Valentinian I, is named co-Augustus at the age of eight by his father. 394 – The Graffito of Esmet-Akhom, the latest known inscription in Egyptian hieroglyphs, is written. 410 – The Visigoths under king Alaric I begin to pillage Rome. 1185 – Sack of Thessalonica by the Normans. 1200 – King John of England, signer of the first Magna Carta, marries Isabella of Angoulême in Angoulême Cathedral. 1215 – Pope Innocent III issues a bull declaring Magna Carta invalid.
March 30598 – Balkan Campaign: The Avars lift the siege at the Byzantine stronghold of Tomis. Their leader Bayan I retreats north of the Danube River after the Avaro-Slavic hordes are decimated by the plague. 1282 – The people of Sicily rebel against the Angevin king Charles I, in what becomes known as the Sicilian Vespers. 1296 – Edward I sacks Berwick-upon-Tweed, during armed conflict between Scotland and England. 1699 – Guru Gobind Singh establishes the Khalsa in Anandpur Sahib, Punjab.
November 15655 – Battle of the Winwaed: Penda of Mercia is defeated by Oswiu of Northumbria. 1315 – Growth of the Old Swiss Confederacy: The Schweizer Eidgenossenschaft ambushes the army of Leopold I in the Battle of Morgarten. 1532 – Spanish conquest of the Inca Empire: Commanded by Francisco Pizarro, Spanish conquistadors under Hernando de Soto meet Incan Emperor Atahualpa for the first time outside Cajamarca, arranging for a meeting in the city plaza the following day. 1533 – Francisco Pizarro arrives in Cuzco, the capital of the Inca Empire.
January 18474 – Seven-year-old Leo II succeeds his maternal grandfather Leo I as Byzantine emperor. He dies ten months later. 532 – Nika riots in Constantinople fail. 1126 – Emperor Huizong abdicates the Chinese throne in favour of his son Emperor Qinzong. 1486 – King Henry VII of England marries Elizabeth of York, daughter of Edward IV, uniting the House of Lancaster and the House of York. 1562 – Pope Pius IV reopens the Council of Trent for its third and final session. 1586 – The magnitude 7.
September 336 BC – In the Battle of Naulochus, Marcus Vipsanius Agrippa, admiral of Octavian, defeats Sextus Pompey, son of Pompey, thus ending Pompeian resistance to the Second Triumvirate. 301 – San Marino, one of the smallest nations in the world and the world's oldest republic still in existence, is founded by Saint Marinus. 590 – Consecration of Pope Gregory I (Gregory the Great). 673 – King Wamba of the Visigoths puts down a revolt by Hilderic, governor of Nîmes (France) and rival for the throne.
December 291170 – Thomas Becket, Archbishop of Canterbury, is assassinated inside Canterbury Cathedral by followers of King Henry II; he subsequently becomes a saint and martyr in the Anglican Communion and the Catholic Church. 1503 – The Battle of Garigliano was fought between a Spanish army under Gonzalo Fernández de Córdoba and a French army commanded by Ludovico II, Marquess of Saluzzo. 1607 – According to John Smith, Pocahontas, daughter of Powhatan leader Wahunsenacawh, successfully pleads for his life after tribal leaders attempt to execute him.
June 281098 – Fighters of the First Crusade defeat Kerbogha of Mosul at the battle of Antioch. 1360 – Muhammed VI becomes the tenth Nasrid king of Granada after killing his brother-in-law Ismail II. 1461 – Edward, Earl of March, is crowned King Edward IV of England. 1495 – A French force heavily defeats a much larger Neapolitan and Spanish army at the battle of Seminara, leading to the creation of the Tercios by Gonzalo de Córdoba. 1519 – Charles V is elected Emperor of the Holy Roman Empire.
July 26657 – First Fitna: In the Battle of Siffin, troops led by Ali ibn Abu Talib clash with those led by Muawiyah I. 811 – Battle of Pliska: Byzantine Emperor Nikephoros I is killed and his heir Staurakios is seriously wounded. 920 – Rout of an alliance of Christian troops from Navarre and Léon against the Muslims at the Battle of Valdejunquera. 1309 – The Holy Roman Emperor Henry VII is recognized King of the Romans by Pope Clement V. 1509 – The Emperor Krishnadevaraya ascends to the throne, marking the beginning of the regeneration of the Vijayanagara Empire.
